Rather than shoe-horn it them into FLEx, may I recommend you try out SayMore, FLEx’s companion tool that is designed to do exactly that kind of thing. If you later transcribe any of those texts, SayMore will help you do it in a time-aligned way, and then export a “FLExText” for interlinearizing in FLEx.
John Hatton
SIL International Language Software Development, PALASO, and SIL Papua New Guinea